Date: Fri, 1 Nov 2019 12:34:02 -0700 From: John Baldwin <jhb@FreeBSD.org> To: luporl <luporl@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r354239 - head/contrib/gdb/gdb Message-ID: <a33ec625-02d8-6203-67ec-6355b0954808@FreeBSD.org> In-Reply-To: <CAC7XEcKTgfn53qRnHc_5j3q=rNki-KXGYLW7q=Fm2_f6M5J%2Bnw@mail.gmail.com> References: <201911011128.xA1BShOC057227@repo.freebsd.org> <f54f6537-de01-02a2-e2c2-221f8acb859f@FreeBSD.org> <CAC7XEcKTgfn53qRnHc_5j3q=rNki-KXGYLW7q=Fm2_f6M5J%2Bnw@mail.gmail.com>
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On 11/1/19 12:26 PM, luporl wrote: > Well, after evaluating remote kernel debugging through serial port, on > amd64, I've run into several issues while using latest ports gdb/kgdb. > I don't remember all of them, but were things like step/next not always > working, connection being lost, and similar things. > OTOH, /usr/libexec/kgdb worked fine and reliably, although older and more > limited. > This is probably due to some incompatibility in GDB Remote Serial Protocol, > between the kernel backend and newer GDB from ports. > > So, that's why I chose to use /usr/libexec/kgdb while fixing/enabling > remote debugging on PPC64, because it works reasonably well, and I could > focus on testing/fixing other parts first. > With only this change on gdb, it is now possible to use it to test some > basic functionality, like remote debugger attach, backtrace and data > inspection. > > My goal is not to fix every issue in /usr/libexec/kgdb, but just to get the > basics working, to then move on and switch to ports' GDB. What's odd about this commit is it only affects userland binaries, not the kernel, so a bit odd for kgdb, especially since the old kgdb in the tree doesn't include user support IIRC, only kernel bits (in modern gdb, kgdb is just a wrapper, and you can use 'target vmcore' from within gdb itself against a crash dump, etc.) -- John Baldwin
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